Metal-oxide-metal (MOM) (or more generally metal-dielectric-metal) capacitors are a known device for use in integrated circuits, and commonly include multiple layers of patterned metal conductors with intervening layers of metal oxide or other insulating dielectric materials to prevent unwanted shorts between successive conductor layers. For brevity, the term “MOM” is hereby defined and shall be understood to mean “metal-dielectric-metal,” except in instances where expressly stated otherwise or made clear from the context to have a different meaning, where ‘dielectric’ may be, for example, an insulating dielectric material such as a metal oxide.” For like reasons, reference in this description to an “oxide” layer of a “MOM” structure will be understood to mean a reference to an “insulating dielectric layer,” for example a “metal oxide.”
One known type of MOM capacitor is generally termed a MOM “finger capacitor.” One general structure of a MOM finger capacitor is two comb-like conductor patterns, each comprising a set of fingers extending from a frame, aligned such that the two sets of fingers are parallel and interdigitated. One of the comb-like structures is an “anode” and the other a “cathode,” The interdigitated fingers thereby form a plurality of finger pairs, each comprising one anode finger extending parallel to one cathode finger. Each of these pairs, in turn, forms a capacitor element, often termed a “sub-capacitor.” The total capacitance of the interdigitated arrangement is, to a first order approximation, the sum of the sub-capacitors.
As known in the conventional IC capacitor arts, design and fabrication targets of MOM finger capacitors can include high capacitance density, meaning high capacitance per unit area occupied on the IC, and a low real resistance. As also known in the conventional arts, constraints can arise in design and fabrication toward these and other targets. For example, adjusting values of certain structural parameters of conventional MOM finger capacitors to increase capacitor density can create an unwanted increase in real resistance and/or reduction of reliability.